Batsman Pietersen was dropped from the squad over the weekend following allegations that he had sent text messages to members of the South African team which criticised some of his England teammates.
Pietersen's omission has resulted in Jonny Bairstow being recalled and Bresnan believes that the youngster can more than fill the void.
"It may be an even better side, it's one of those things where a talented player is being replaced by another talented player, Bresnan told Sky Sports News. "Why should we miss a certain individual because he's unavailable for selection?"
England currently trail the three-match series 1-0 with two matches played.